Objective: To investigate whether assessment of tissue oxygenation could help personalizing the mean arterial pressure (MAP) target in patients with septic shock.
Methods: We prospectively measured near-infrared spectroscopy variables in 22 patients with septic shock receiving norepinephrine with a MAP>75 mmHg within the first six hours of intensive care unit (ICU) stay for patients with community-acquired septic shock and within the first six hours of resuscitation for patients with ICU-acquired septic shock. All measurements were performed at MAP>75 mmHg ("high-MAP") and at MAP 65-70 mmHg ("low-MAP") after decreasing the norepinephrine dose. Relative changes in StO2 recovery slope (RS) >8% were considered clinically relevant.
Results: After decreasing the norepinephrine dose by 45 ± 24%, MAP significantly decreased from 81[78;84] to 68[67;69]mmHg, whereas cardiac index did not change. On average, the StO2-RS significantly decreased between high and low-MAP from 2.86[1.87;4.32] to 2.41[1.14;3.72]%/sec with a large interindividual variability: the StO2-RS decreased by >8% in 14 patients, increased by >8% in 4 patients and changes were < 8% in 4 patients. These changes in StO2-RS were correlated with the StO2-RS at low-MAP (r = 0.57,p = 0.006). At high-MAP, there was no difference between patients exhibiting a relevant decrease or increase in StO2-RS.
Conclusions: A unique MAP target may not be suitable for all patients with septic shock as its impact on peripheral oxygenation may widely differ among patients. It could make sense to personalize MAP target through a multimodal assessment including peripheral oxygenation.
Keywords: Intensive care unit; Near-infrared spectroscopy; Recovery slope; Tissue oxygenation.
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